Answers

I've also seen that in the directories created in the system folder\macromed\flash, there's an OCX file that is difficult to delete, making a deletion of the folders fail and the control panels stay behind. I wound up needing to use cacls to set administrators to full permissions on the OCX files in both system directories in order to enable deleting the files. That only worked at uninstall - if you set the file permissions at install, Flash isn't recognized.

Also: there is a settings.sol file that stores hardware acceleration settings. If you have hardware acceleration disabled, delete that file (it's in the user profiles) and that will re-enable hardware acceleration.